CN211825683U - Optical fiber heavy metal ion sensor based on Fabry-Perot interference - Google Patents

Abstract

The utility model discloses an optical fiber heavy metal ion sensor based on Fabry-Perot interference, comprising a single-mode optical fiber, a quartz glass capillary, a high borosilicate glass, and an active layer; the single-mode optical fiber is inserted into a through hole of the quartz glass capillary, and the quartz glass capillary One end face of the borosilicate glass is fixedly connected to one end face of the borosilicate glass; the other end face of the borosilicate glass is fixedly connected to one end face of the active layer. Using the advantages of optical fiber interference and the subtle changes in the refractive index and thickness of the modified polymer compounds after adsorbing heavy metal ions, the interference fringes are changed. The concentration of heavy metal ions can be effectively evaluated for heavy metal pollution in the environment or food. At the same time, the change amount of the interference fringe caused by the change of the active layer due to the change of the ambient temperature can be eliminated by the change information of the interference fringe caused by the change of the high boron silicon thickness, thereby improving the measurement accuracy of the heavy metal ions.

Description

A Fiber Optic Heavy Metal Ion Sensor Based on Fabry-Perot Interference

technical field

The utility model relates to the field of heavy metal ion detection, in particular to an optical fiber heavy metal ion sensor based on Fabry-Perot interference.

Background technique

With the rapid development of the national economy and society, various industrial wastewater discharge, sewage irrigation, unreasonable and practical use of chemical fertilizers, air pollution and other phenomena continue to occur, and the environment, water resources, and soil are increasingly polluted by heavy metals. Heavy metal ions are difficult to degrade and are easily absorbed by the human body through drinking water or the food chain. Heavy metal ions are deposited and enriched in the human body. When the concentration exceeds a certain concentration, they will be toxic to the human body, causing direct harm to the body and endangering human health. The absorption of heavy metal elements by the human body will lead to protein denaturation, inactivation of enzymes, and structural and functional damage to tissue cells. Therefore, the detection of heavy metal content is very important to people's healthy life. Research on selective and highly sensitive detection of heavy metal ions method is important.

The traditional detection methods of heavy metal content mainly include atomic absorption spectrometry, atomic emission spectrometry, atomic fluorescence spectrometry, mass spectrometry, enzyme inhibition method and electrochemical analysis and detection method. The analysis and testing methods of these instruments have their own advantages, but the detection is cumbersome, time-consuming, and complicated to operate, which has always plagued the current detection of heavy metal ions. There is an urgent need for a sensor that can detect the content of heavy metal ions conveniently, quickly and with high sensitivity.

Utility model content

The purpose of the present utility model is to provide an optical fiber heavy metal ion sensor based on Fabry-Perot interference, so as to solve the problems existing in the above-mentioned prior art, and can efficiently measure the heavy metal ion content in the environment.

In order to achieve the above purpose, the utility model provides the following solutions: the utility model provides an optical fiber heavy metal ion sensor based on Fabry-Perot interference, comprising a single-mode optical fiber, a quartz glass capillary, a high borosilicate glass, and an active layer;

The single-mode optical fiber is inserted into the quartz glass capillary, and one end of the single-mode optical fiber protrudes from one end of the quartz glass capillary; the other end of the quartz glass capillary is fixedly connected to one end of the borosilicate glass;

The other end of the borosilicate glass is fixedly connected to one end of the active layer.

Preferably, the inner diameter of the quartz glass capillary is 126-128 microns, and the outer diameter is 1-2.5 mm; the thickness of the borosilicate glass is 100-500 microns.

Preferably, the end face of the quartz glass capillary in contact with the borosilicate glass and the end face of the single-mode optical fiber in contact with the borosilicate glass should have a smoothness of grade 12 or above.

Preferably, the single-mode optical fiber and the quartz glass capillary are fixedly connected by epoxy glue.

The utility model discloses the following technical effects: the utility model utilizes the advantages of optical fiber interference and the modified polymer compound absorbs heavy metal ions to cause subtle changes in its refractive index and thickness, thereby causing changes in interference fringes. The algorithm can quickly, conveniently and highly sensitively measure the concentration of heavy metal ions in the environment, so that it can effectively evaluate the heavy metal pollution in the environment or food. At the same time, the thickness of the borosilicate glass will change when the ambient temperature changes, and the thickness of the active layer will also change. Therefore, the change information of the interference fringes caused by the thickness change of the borosilicate glass can be used to eliminate the change of the active layer due to the ambient temperature. The amount of interference fringes caused by the change, thereby improving the measurement accuracy of heavy metal ions.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings required in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only of the present invention. For some embodiments of the present invention, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without any creative effort.

Fig. 1 is the structure diagram of the optical fiber heavy metal ion sensor based on Fabry-Perot interference of the present invention;

Fig. 2 is the optical signal transmission principle diagram of the optical fiber heavy metal ion sensor based on Fabry-Perot interference of the present invention;

3 is a schematic diagram of a system for detecting heavy metal ions using the optical fiber heavy metal ion sensor based on Fabry-Perot interference of the present invention;

Among them, 1 is a single-mode fiber, 2 is a quartz glass capillary, 3 is a high borosilicate glass, 4 is an active layer, 5 is a first reflecting surface, 6 is a second reflecting surface, 7 is the exposed side end surface of the active layer, 8 is the optical signal reflected from the interface between the end face of the quartz glass capillary and the borosilicate glass, 9 is the optical signal reflected from the interface between the borosilicate glass and the active layer, 10 is the optical signal reflected from the surface of the active layer, 11 is the light source, 12 It is an optical fiber coupler, 13 is a container for storing heavy metal ion solution, 14 is a heavy metal ion sensor, and 15 is a signal demodulation and output display device.

Detailed ways

The technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the implementations. example. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

In order to make the above objects, features and advantages of the present utility model more clearly understood, the present utility model will be described in further detail below with reference to the accompanying drawings and specific embodiments.

As shown in FIG. 1 , the present invention provides an optical fiber heavy metal ion sensor based on Fabry-Perot interference, comprising a single-mode optical fiber 1 , a quartz glass capillary 2 , a high borosilicate glass 3 , and an active layer 4 . Structurally, the peripheral surface of the single-mode optical fiber 1 is coated with epoxy glue OE188 and then inserted into the through hole of the quartz glass capillary 2 with one side of the two end faces flush, and one side of the quartz glass capillary 2 is flush. The end face is fixedly connected to one end face of the borosilicate glass 3 ; the other end face of the borosilicate glass 3 is fixedly connected to one end face of the active layer 4 .

To further optimize the plan, the inner diameter of the quartz glass capillary 2 is 126-128 microns, and the outer diameter is 1-2.5 mm; the thickness of the high borosilicate glass 3 is 100-500 microns. At the same time, the quartz glass capillary 2 and the high borosilicate glass 3 are in phase The end face in contact, the end face of the single-mode optical fiber 1 and the high borosilicate glass 3 should have a smoothness of grade 12 or above. The single-mode fiber and the quartz glass capillary are fixedly connected by epoxy glue OE188.

The measurement principle of the optical fiber heavy metal ion sensor based on Fabry-Perot interference of the present invention will be described below with reference to Figures 2-3.

As shown in Fig. 2, due to the difference in refractive index between the quartz glass capillary 2 and the borosilicate glass 3, in a physical sense, the end face 5 in contact with the quartz glass capillary 2 and the borosilicate glass 3 is formed as the first reflection surface. Reflecting surface; the refractive index of the high borosilicate glass 3 and the active layer 4 are also different, forming a second reflecting surface 6; the first reflecting surface 5 and the second reflecting surface 6 constitute two parts of the first Fabry-Perot cavity. The second reflective surface 6 and the surface 7 of the active layer 4 constitute two reflective surfaces of the second Fabry-Perot cavity. The optical signal of the optical fiber is transmitted from left to right, and when it is transmitted to the second reflecting surface 6, a partial reflection 8 occurs, that is, the optical signal reflected from the interface between the end face of the quartz glass capillary 2 and the borosilicate glass 3, and the remaining optical signal is reflected in the borosilicate glass. The glass 3 continues to transmit to the right, and when it is transmitted to the interface 6, that is, the second reflective surface, it will also generate a partial reflection 9, that is, the optical signal reflected by the interface between the high borosilicate glass 3 and the active layer 4, and then the remaining optical signal is in The active layer 4 continues to transmit to the right, and finally reflects on the outer surface 7 of the active layer 4. The optical signal 8 reflected by the end face of the quartz glass capillary 2 and the interface of the high borosilicate glass 3 and the difference between the high borosilicate glass and the active layer are reflected. The optical signal 9 reflected by the interface interferes, and the optical signal 9 reflected from the interface between the borosilicate glass 3 and the active layer 4 interferes with the optical signal 10 reflected from the surface of the active layer. The end face of the quartz glass capillary 2 and the borosilicate glass 3 interfere. The optical signal 8 reflected by the interface and the optical signal 10 reflected by the surface of the active layer also interfere (this interference signal can be ignored when extracting the sensing signal). After the active layer 4 adsorbs heavy metal ions, its refractive index or thickness will change. At this time, the interference signal generated by the optical signal 9 reflected by the interface between the borosilicate glass 3 and the active layer 4 and the optical signal 10 reflected by the surface of the active layer will be The change reflects the change in the content of heavy metal ions; when the ambient temperature changes, the thickness of the borosilicate glass 3 also changes. The interference signal generated by the optical signal 9 reflected by the interface between the borosilicate glass and the active layer will change, and the optical signal 9 reflected by the interface between the borosilicate glass 3 and the active layer 4 and the optical signal 10 reflected by the surface of the active layer The interference signal will also change, so the total change of the optical signal 9 reflected from the interface between the borosilicate glass 3 and the active layer 4 and the optical signal 10 reflected from the surface of the active layer can be based on the optical signals 8 and 9 reflected from the interface. The variation of the interference signal eliminates the error caused by temperature when detecting the concentration of heavy metal ions.

As shown in FIG. 3 , the heavy metal ion sensor 14 is placed in the container 13 storing the heavy metal ion solution. The light signal from the light source 11 reaches the heavy metal ion sensor 14 through the optical fiber coupler 12 and the optical fiber. The reflected interference signal is sent to the signal demodulation and output display device 15 through the fiber coupler 12 and the fiber for demodulation and output display.

The utility model utilizes the advantages of optical fiber interference and the slight change of the refractive index and thickness of the modified polymer compound after adsorbing heavy metal ions, thereby causing the change of interference fringes. The concentration of heavy metal ions in the environment is measured, which enables an effective assessment of heavy metal contamination in the environment or food. At the same time, the thickness of the borosilicate glass will change when the ambient temperature changes, and the thickness of the active layer will also change. Therefore, the change information of the interference fringes caused by the thickness change of the borosilicate glass can be used to eliminate the change of the active layer due to the ambient temperature. The amount of interference fringes caused by the change, thereby improving the measurement accuracy of heavy metal ions.

In the description of the present invention, it should be understood that the terms "portrait", "horizontal", "upper", "lower", "front", "rear", "left", "right", "vertical" , "horizontal", "top", "bottom", "inside", "outside" and other indications of orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, only for the convenience of describing the present utility model, not Indicates or implies that the referred device or element must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as a limitation of the present invention.

The above-mentioned embodiments are only to describe the preferred mode of the present invention, and do not limit the scope of the present invention. Under the premise of not departing from the design spirit of the present invention, those of ordinary skill in the art can make the technical solutions of the present invention. Various deformations and improvements made shall fall within the protection scope determined by the claims of the present utility model.

Claims (4)

1. An optical fiber heavy metal ion sensor based on Fabry-Perot interference is characterized by comprising a single-mode optical fiber, a quartz glass capillary tube, high borosilicate glass and an active layer;

the single-mode optical fiber is inserted into the quartz glass capillary, and one end of the single-mode optical fiber extends out of one end of the quartz glass capillary; the other end of the quartz glass capillary tube is fixedly connected with one end of the high borosilicate glass;

the other end of the high borosilicate glass is fixedly connected with one end of the active layer.

2. The Fabry-Perot interference-based optical fiber heavy metal ion sensor according to claim 1, wherein the quartz glass capillary has an inner diameter of 126-128 μm and an outer diameter of 1-2.5 mm; the thickness of the high borosilicate glass is 100-500 microns.

3. The fabry-perot interference based optical fiber heavy metal ion sensor according to claim 1, wherein the end face of the quartz glass capillary contacting the borosilicate glass, and the end face of the single mode optical fiber contacting the borosilicate glass, have a finish of 12 or more.

4. The fabry-perot interference based fiber optic heavy metal ion sensor of claim 1, wherein: the single-mode optical fiber and the quartz glass capillary are fixedly connected through epoxy glue.

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